Okay Andy,
I am listening hard. I have OTS comms, Depth sounder yes, Surface beacon
and VHF. What are you recommending for Number 3 and 5 Imaging Sonar and
acoustic NAV system. Also what is SBL/USBL?
As always limited budget but not too limited. I followed Cliff's advice on
comms and got scratch and dent 8 channel with diver unit for the sub all for
$3,500. I am a bit leery of Interphase now having heard of the recent
problem but David might fix it. Echo pilot is another forward sonar but I
have not heard of anyone using it. Eventually I would like an INS and I know
there is a guy trying to get one to the market for under 50k. What is
Desert star.s SBL. How does it compare with Linkquest? Hugh
-----Original Message-----
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of andy goldstein
Sent: Tuesday, 16 March 2010 12:43 a.m.
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Desert Star Sport
Hi all.
A couple of points.
An echo-sounder, fish finder, etc. as normally installed would require
the surface vessel to be almost on-top of the sub. A side scan
typically would require the surface boat to always be moving back and
forth with the sub broadside in order to image. I think both would have
pretty sever operational challenges when trying to track a sub.
The sport/scout do require the receiver to be in the water. As
delivered the sonar transducer and display electronics are co-located in
the same housing. So, yes you would get wet when attempting to use if
from a surface boat.
It would be fairly simple to open up the receiver, disconnect the sonar
transducer from the display electronics, connect it to a coax cable, and
run the display electronics remotely (like on a pole or in the cabin).
This would void the warranty... Remember that the transducer is
directional, so if it's rigidly mounted the relative positions of the
sub and chase boat would have to stay constant. You could run spirals
or something if you lost contact. If you do rigidly mount the receiver
I'd get a second one too. That way if you had to send divers or an rov
down to the sub you could relocate it easier.
A configuration which would be more like the typical diver application,
would be to pinger on a pole off the boat, and the receiver on the sub.
The sub could always get back the surface boat without surfacing.
If you want to move up to a "real" tracking system. There are lots.
Desert star has an sbl for about $10K, Linkquest was mentioned at $15K
for their USBL, then there is sonardyne, tritech, applied acoustics,
ORE, ixsea. I think that is everyone. There are companies like
Asthtead which rent these systems, which may be an option.
If I had to had to have a fixed budget though I'd get other gear before
a nav system I think.
1) Comms, like a OTS phone or something
2) Altimeter/depth sounder on the sub
3) Some imaging sonar, scanning or multibeam if I had the $$
4) Surface beacon (strobe/radio)
5) SBL/USBL acoustic nav system.
On 3/15/2010 12:18 AM, Jon Wallace wrote:
Frank,
Not addressed to me, but I'll throw in my two cents. Most commercial
pingers are ultrasonic. The hydrophone that David came up with uses a
"sonic" piezo element centered at around 3khz so it would not be
resonant to the higher frequency commercial pingers and would not
detect them.
The Desert Star scuba pingers provide both direction and range and can
be used exactly as you've described. Unfortunately we have never been
able to succeed at getting directionality out of the HBH (home-built
hydrophone) using 3khz piezo elements, however my experience was that
it was very easy to determine range based upon the loudness of the
"ping". Therefore, by running a grid-pattern you could "home" in on
the pinger by just listening to whether the sound was getting louder
or softer. Not the most efficient way of finding an object by any
means, however, and similar to what you would have to do with a
down-looking sonar or fish finder.
Jon
ShellyDalg@aol.com wrote:
In a message dated 3/14/2010 8:06:39 P.M. Pacific Daylight Time,
alanjames@xtra.co.nz writes:
I have only had experience with cheap fish finders& have
questions about their reliability,
Hi David and Alan. Gulping air......well, OK.
Now back to the question of finding a sub......
If a sub has a pinger attached, could a surface boat find it with the
hydrophone you ( David ) made ?
Depending on directionality of the array, a direction for the sub's
location should be possible. Maybe then the pilot could motor over in
that direction and as the pinger got louder you may be able to tell
how close you're getting. At least staying within a pre-set minimum
distance. By rotating the pick-up you would know if the surface boat
needs to go left or right. Now, if you passed OVER the sub and the
pinger signal was now coming from behind the pick-up the pilot would
then stop or get out of the way in case the sub was ascending to the
surface. Be a bummer to ram your own surface crew.
Maybe you could have two pingers with one stronger ( louder ) or more
frequent so by listening you'd be able to tell how close you were.
What makes a pinger anyway ? Is it just a thing that sends out a
sound wave at a set interval ? It seems the pick-up part is the hard
piece to make. So the returning signal can be figured how far away it
is ( function of time ? ) and what direction it's coming from ( array
set-up in degrees ?)
Frank D.
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